Metric system's growth challenges U.S. firms

MAUMEE, Ohio—Scott Campbell, Eaton P.L.C.'s marketing manager for specialty hose and connectors, remembers going through school in the 1970s and 1980s, and lessons focused on how the U.S. soon would convert to the metric systems.

“Here we are in 2014, and it hasn't happened yet,” said Campbell, who is based at Eaton's Maumee location.

And that has become an increasing problem in industry, he said, as companies in the U.S.—the only industrialized nation not on the metric system—often must deal with both English and metric systems. That is especially true in the hydraulics industry, where with consolidation and globalization, it often means that suppliers of hose, tubing, ports and connectors either must offer components in both measurements or offer some sort of adaptor connection system.

“What we have in the U.S. is this mixing and matching of metric and English measurements,” Campbell said. “There's been a lot of work done in the U.S. to accommodate both types of systems, but the U.S. really hasn't gone over cold turkey to the metric system yet, and to be quite honest with you, I can't see it happening in the near future.”

In the rubber and plastics industry specific to hose and tubing, the problem is that manufacturers use multiple types of connections, depending on where they are located. “When we look at equipment that companies in Europe or China manufacture, it's mainly metric,” he said. “And we are seeing a lot of equipment that's produced in China, Japan or Europe moved into the U.S. or Canada, and a lot of that equipment has metric connections on it and not necessarily the inch connections everybody's used to in the U.S.”

With consolidation, some foreign equipment makers are putting transplant operations into the U.S. but using the same design from their headquarters country, resulting in more metrics on equipment being produced domestically.

Because of that, those firms supporting transplants must be able to offer metric connections along with traditional inch connections, according to Campbell.

For example, most automotive plants operate on the metric system in the U.S. and have machinery brought in from foreign countries. “When it comes time to repair the equipment, the local distributor who services those plants has to be able to accommodate connections,” he said. “You have to offer more part numbers because metrics are not as popular (in the U.S.) as inch connections. We have to guess at times as to what you need to have on your shelves. It makes the manufacturers do more legwork and understanding of what those part numbers need to be for us to be put on the shelf at anytime.”

Widespread issue

The issue isn't focused on any one market sector, Campbell said. The industries where this is happening include, among others, ag/construction equipment; material handling; oil and gas; injection molding; railway systems; and alternative energy.

Besides the proliferation of part numbers, it brings about the need for companies such as Eaton to educate its distributors and employees. While it seems straightforward in theory, being able to identify the difference between an English or metric part in the field is more complicated.

“The last thing you want to do is put an inch connection in a metric port and then have it blow up,” Campbell said. “It puts a lot of onus on manufacturers to make sure distributors and sales forces are trained.”

Eaton has incorporated its training on metrics into its standard training curriculum, he said. It covers metric tube fittings, which the firm supplies with its Walterscheid product line; how to recognize hose ends produced in Europe or China and brought into the U.S. and need metric connections; and the use of port adaptors, where one end could be metric and the other in inches.

While it is becoming more common, Campbell estimates no more than 10-20 percent of what is used in the U.S. is metric at this time. “It's heavier in certain markets than others,” he said. “The markets that are dominated by traditional U.S. companies have less metrics. But in markets such as injection molding or auto equipment dominated by international players, you see metrics all over the place.”

Eaton mainly supplies metrics in the U.S. through its global manufacturing network and stocks parts so they are ready when needed. “For the most part Eaton does not manufacture the metrics in North America and probably won't going forward just for the fact they're a lot more common outside the U.S.,” Campbell said.

View of a standards veteran

Paul DeWitt, manager of engineering services in Eaton's Hydraulics Group, has been an engineer for 30 years and involved in standards committees for 15. He attends both ISO and SAE standards meetings and has seen most standards converted to metrics, but that hasn't necessarily translated into changes in the marketplace.

Most standards for fluid connectors within SAE have been converted to metric, he said. It was a gradual process that initially used the inch as the primary specification, with metrics secondary. Then it flip-flopped, with metrics listed as primary. In many cases, the inch dimensions were moved to an appendix and eventually removed from the standard entirely.

Even with that evolution, Eaton still sees much less demand for metric ports and connectors, DeWitt said. “Some part of it has to do with North America's resistance to go metric,” he said. “Even though the automotive industry has embraced it widespread, it has not taken place in the hydraulics industry. It's been frustrating because we've had to deal with dual dimensioning still. It's such a waste of time.”

From the viewpoint of the standards committees, the desire is to have a single metric standard wherever possible. “Even SAE has had some level of receptiveness to not creating a standard that's already ISO,” DeWitt said.

That the progress hasn't been faster can be frustrating to those on committees. “We walk out of there and say we know this is the right thing to do,” he said. “Now, will our companies actually follow those policies? Maybe soon, maybe later. All we can do is take back the proposals to our companies and try to sell them.”

At Eaton, DeWitt said there has been a certain level of acceptance, but it's slow in some respects. When a drawing is made with metrics as the spec, some at the plant level may push back and fight to convert it into English dimensions.

“You can put dual dimensions on a drawing, but that takes extra effort,” he said. “And you're spending a lot of time on the floor changing things, exposing yourself to errors.”

Going forward

Campbell said that Eaton, based on feedback, has identified three types of distributors. The first is reluctant to change and would rather continue to convert to English dimensions to keep things simple. A second group—dubbed “dabblers”—reluctantly will support metrics, keeping certain products in stock.

The third, he said, are those that have parts on the shelves at all times to service original equipment cus-tomers and maintenance and repair orders. “They will be proactive and have that niche it can support and can get a higher price because they have the product at all times,” he said.

Campbell expects the penetration of metrics to continue to grow, perhaps hitting 25-35 percent in a decade and maybe 50 percent in two decades. “As more consolidation and globalization occurs, you will see more expedited adoption of metrics in the U.S.,” he said.

DeWitt said as long as the customer isn't demanding it, then it will be harder to make it a policy. As an engineer and standards committee member, though, he has his own take.

“I think it will continue to be a little bit of an arm wrestling match,” he said. “My own personal philosophy is, "Go metric or you're an idiot.' But that's mine. I don't speak for Eaton or for anybody else. That's just from an engineer's standpoint. Metric is very easy for my brain to process.”